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>Appendix E. Release Notes</TD
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CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="RELEASE-7-4"
>E.145. Release 7.4</A
></H1
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Release Date: </B
>2003-11-17</P
></BLOCKQUOTE
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN125647"
>E.145.1. Overview</A
></H2
><P
>   Major changes in this release:
  </P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="LITERAL"
>IN</TT
> / <TT
CLASS="LITERAL"
>NOT IN</TT
> subqueries are
     now much more efficient</DT
><DD
><P
>      In previous releases, <TT
CLASS="LITERAL"
>IN</TT
>/<TT
CLASS="LITERAL"
>NOT
      IN</TT
> subqueries were joined to the upper query by
      sequentially scanning the subquery looking for a match.  The
      7.4 code uses the same sophisticated techniques used by
      ordinary joins and so is much faster.  An
      <TT
CLASS="LITERAL"
>IN</TT
> will now usually be as fast as or faster
      than an equivalent <TT
CLASS="LITERAL"
>EXISTS</TT
> subquery; this
      reverses the conventional wisdom that applied to previous
      releases.
     </P
></DD
><DT
>Improved <TT
CLASS="LITERAL"
>GROUP BY</TT
> processing by using hash buckets</DT
><DD
><P
>      In previous releases, rows to be grouped had to be sorted
      first.  The 7.4 code can do <TT
CLASS="LITERAL"
>GROUP BY</TT
>
      without sorting, by accumulating results into a hash table
      with one entry per group.  It will still use the sort
      technique, however, if the hash table is estimated to be too
      large to fit in <TT
CLASS="VARNAME"
>sort_mem</TT
>.
     </P
></DD
><DT
>New multikey hash join capability</DT
><DD
><P
>      In previous releases, hash joins could only occur on single
      keys.  This release allows multicolumn hash joins.
     </P
></DD
><DT
>Queries using the explicit <TT
CLASS="LITERAL"
>JOIN</TT
> syntax are
     now better optimized</DT
><DD
><P
>      Prior releases evaluated queries using the explicit
      <TT
CLASS="LITERAL"
>JOIN</TT
> syntax only in the order implied by
      the syntax. 7.4 allows full optimization of these queries,
      meaning the optimizer considers all possible join orderings
      and chooses the most efficient.  Outer joins, however, must
      still follow the declared ordering.
     </P
></DD
><DT
>Faster and more powerful regular expression code</DT
><DD
><P
>      The entire regular expression module has been replaced with a
      new version by Henry Spencer, originally written for Tcl.  The
      code greatly improves performance and supports several flavors
      of regular expressions.
     </P
></DD
><DT
>Function-inlining for simple SQL functions</DT
><DD
><P
>      Simple SQL functions can now be inlined by including their SQL
      in the main query.  This improves performance by eliminating
      per-call overhead.  That means simple SQL functions now
      behave like macros.
     </P
></DD
><DT
>Full support for IPv6 connections and IPv6 address data types</DT
><DD
><P
>      Previous releases allowed only IPv4 connections, and the IP
      data types only supported IPv4 addresses. This release adds
      full IPv6 support in both of these areas.
     </P
></DD
><DT
>Major improvements in SSL performance and reliability</DT
><DD
><P
>      Several people very familiar with the SSL API have overhauled
      our SSL code to improve SSL key negotiation and error
      recovery.
     </P
></DD
><DT
>Make free space map efficiently reuse empty index pages,
     and other free space management improvements</DT
><DD
><P
>      In previous releases, B-tree index pages that were left empty
      because of deleted rows could only be reused by rows with
      index values similar to the rows originally indexed on that
      page. In 7.4, <TT
CLASS="COMMAND"
>VACUUM</TT
> records empty index
      pages and allows them to be reused for any future index rows.
     </P
></DD
><DT
>SQL-standard information schema</DT
><DD
><P
>      The information schema provides a standardized and stable way
      to access information about the schema objects defined in a
      database.
     </P
></DD
><DT
>Cursors conform more closely to the SQL standard</DT
><DD
><P
>      The commands <TT
CLASS="COMMAND"
>FETCH</TT
> and
      <TT
CLASS="COMMAND"
>MOVE</TT
> have been overhauled to conform more
      closely to the SQL standard.
     </P
></DD
><DT
>Cursors can exist outside transactions</DT
><DD
><P
>      These cursors are also called holdable cursors.
     </P
></DD
><DT
>New client-to-server protocol</DT
><DD
><P
>      The new protocol adds error codes, more status information,
      faster startup, better support for binary data transmission,
      parameter values separated from SQL commands, prepared
      statements available at the protocol level, and cleaner
      recovery from <TT
CLASS="COMMAND"
>COPY</TT
> failures.  The older
      protocol is still supported by both server and clients.
     </P
></DD
><DT
><SPAN
CLASS="APPLICATION"
>libpq</SPAN
> and
     <SPAN
CLASS="APPLICATION"
>ECPG</SPAN
> applications are now fully
     thread-safe</DT
><DD
><P
>      While previous <SPAN
CLASS="APPLICATION"
>libpq</SPAN
> releases
      already supported threads, this release improves thread safety
      by fixing some non-thread-safe code that was used during
      database connection startup.  The <TT
CLASS="COMMAND"
>configure</TT
>
      option <TT
CLASS="OPTION"
>--enable-thread-safety</TT
> must be used to
      enable this feature.
     </P
></DD
><DT
>New version of full-text indexing</DT
><DD
><P
>      A new full-text indexing suite is available in
      <TT
CLASS="FILENAME"
>contrib/tsearch2</TT
>.
     </P
></DD
><DT
>New autovacuum tool</DT
><DD
><P
>      The new autovacuum tool in
      <TT
CLASS="FILENAME"
>contrib/autovacuum</TT
> monitors the database
      statistics tables for
      <TT
CLASS="COMMAND"
>INSERT</TT
>/<TT
CLASS="COMMAND"
>UPDATE</TT
>/<TT
CLASS="COMMAND"
>DELETE</TT
>
      activity and automatically vacuums tables when needed.
     </P
></DD
><DT
>Array handling has been improved and moved into the server core</DT
><DD
><P
>      Many array limitations have been removed, and arrays behave
      more like fully-supported data types.
     </P
></DD
></DL
></DIV
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN125744"
>E.145.2. Migration to Version 7.4</A
></H2
><P
>   A dump/restore using <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> is
   required for those wishing to migrate data from any previous
   release.
  </P
><P
>   Observe the following incompatibilities:
  </P
><P
></P
><UL
><LI
><P
>     The server-side autocommit setting was removed and
     reimplemented in client applications and languages.
     Server-side autocommit was causing too many problems with
     languages and applications that wanted to control their own
     autocommit behavior, so autocommit was removed from the server
     and added to individual client APIs as appropriate.
    </P
></LI
><LI
><P
>     Error message wording has changed substantially in this
     release.  Significant effort was invested to make the messages
     more consistent and user-oriented.  If your applications try to
     detect different error conditions by parsing the error message,
     you are strongly encouraged to use the new error code facility instead.
    </P
></LI
><LI
><P
>     Inner joins using the explicit <TT
CLASS="LITERAL"
>JOIN</TT
> syntax
     might behave differently because they are now better
     optimized.
    </P
></LI
><LI
><P
>     A number of server configuration parameters have been renamed
     for clarity, primarily those related to
     logging.
    </P
></LI
><LI
><P
>     <TT
CLASS="LITERAL"
>FETCH 0</TT
> or <TT
CLASS="LITERAL"
>MOVE 0</TT
> now
     does nothing.  In prior releases, <TT
CLASS="LITERAL"
>FETCH 0</TT
>
     would fetch all remaining rows, and <TT
CLASS="LITERAL"
>MOVE 0</TT
>
     would move to the end of the cursor.
    </P
></LI
><LI
><P
>     <TT
CLASS="COMMAND"
>FETCH</TT
> and <TT
CLASS="COMMAND"
>MOVE</TT
> now return
     the actual number of rows fetched/moved, or zero if at the
     beginning/end of the cursor.  Prior releases would return the
     row count passed to the command, not the number of rows
     actually fetched or moved.
    </P
></LI
><LI
><P
>     <TT
CLASS="COMMAND"
>COPY</TT
> now can process files that use
     carriage-return or carriage-return/line-feed end-of-line
     sequences. Literal carriage-returns and line-feeds are no
     longer accepted in data values; use <TT
CLASS="LITERAL"
>\r</TT
> and
     <TT
CLASS="LITERAL"
>\n</TT
> instead.
    </P
></LI
><LI
><P
>     Trailing spaces are now trimmed when converting from type
     <TT
CLASS="TYPE"
>char(<TT
CLASS="REPLACEABLE"
><I
>n</I
></TT
>)</TT
> to
     <TT
CLASS="TYPE"
>varchar(<TT
CLASS="REPLACEABLE"
><I
>n</I
></TT
>)</TT
> or <TT
CLASS="TYPE"
>text</TT
>.
     This is what most people always expected to happen anyway.
    </P
></LI
><LI
><P
>     The data type <TT
CLASS="TYPE"
>float(<TT
CLASS="REPLACEABLE"
><I
>p</I
></TT
>)</TT
> now
     measures <TT
CLASS="REPLACEABLE"
><I
>p</I
></TT
> in binary digits, not decimal
     digits.  The new behavior follows the SQL standard.
    </P
></LI
><LI
><P
>     Ambiguous date values now must match the ordering specified by
     the <TT
CLASS="VARNAME"
>datestyle</TT
> setting.  In prior releases, a
     date specification of <TT
CLASS="LITERAL"
>10/20/03</TT
> was interpreted as a
     date in October even if <TT
CLASS="VARNAME"
>datestyle</TT
> specified that
     the day should be first.  7.4 will throw an error if a date
     specification is invalid for the current setting of
     <TT
CLASS="VARNAME"
>datestyle</TT
>.
    </P
></LI
><LI
><P
>     The functions <CODE
CLASS="FUNCTION"
>oidrand</CODE
>,
     <CODE
CLASS="FUNCTION"
>oidsrand</CODE
>, and
     <CODE
CLASS="FUNCTION"
>userfntest</CODE
> have been removed.  These
     functions were determined to be no longer useful.
    </P
></LI
><LI
><P
>     String literals specifying time-varying date/time values, such
     as <TT
CLASS="LITERAL"
>'now'</TT
> or <TT
CLASS="LITERAL"
>'today'</TT
> will
     no longer work as expected in column default expressions; they
     now cause the time of the table creation to be the default, not
     the time of the insertion.  Functions such as
     <CODE
CLASS="FUNCTION"
>now()</CODE
>, <CODE
CLASS="FUNCTION"
>current_timestamp</CODE
>, or
     <CODE
CLASS="FUNCTION"
>current_date</CODE
> should be used instead.
    </P
><P
>     In previous releases, there was special code so that strings
     such as <TT
CLASS="LITERAL"
>'now'</TT
> were interpreted at
     <TT
CLASS="COMMAND"
>INSERT</TT
> time and not at table creation time, but
     this work around didn't cover all cases.  Release 7.4 now
     requires that defaults be defined properly using functions such
     as <CODE
CLASS="FUNCTION"
>now()</CODE
> or <CODE
CLASS="FUNCTION"
>current_timestamp</CODE
>. These
     will work in all situations.
    </P
></LI
><LI
><P
>     The dollar sign (<TT
CLASS="LITERAL"
>$</TT
>) is no longer allowed in
     operator names.  It can instead be a non-first character in
     identifiers.  This was done to improve compatibility with other
     database systems, and to avoid syntax problems when parameter
     placeholders (<TT
CLASS="LITERAL"
>$<TT
CLASS="REPLACEABLE"
><I
>n</I
></TT
></TT
>) are written
     adjacent to operators.
    </P
></LI
></UL
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN125814"
>E.145.3. Changes</A
></H2
><P
>   Below you will find a detailed account of the changes between
   release 7.4 and the previous major release.
  </P
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN125817"
>E.145.3.1. Server Operation Changes</A
></H3
><P
></P
><UL
><LI
><P
>     Allow IPv6 server connections (Nigel Kukard, Johan Jordaan,
     Bruce, Tom, Kurt Roeckx, Andrew Dunstan)
    </P
></LI
><LI
><P
>     Fix SSL to handle errors cleanly (Nathan Mueller)
    </P
><P
>     In prior releases, certain SSL API error reports were not
     handled correctly.  This release fixes those problems.
    </P
></LI
><LI
><P
>     SSL protocol security and performance improvements (Sean Chittenden)
    </P
><P
>     SSL key renegotiation was happening too frequently, causing poor
     SSL performance.  Also, initial key handling was improved.
    </P
></LI
><LI
><P
>     Print lock information when a deadlock is detected (Tom)
    </P
><P
>     This allows easier debugging of deadlock situations.
    </P
></LI
><LI
><P
>     Update <TT
CLASS="FILENAME"
>/tmp</TT
> socket modification times
     regularly to avoid their removal (Tom)
    </P
><P
>     This should help prevent <TT
CLASS="FILENAME"
>/tmp</TT
> directory
     cleaner administration scripts from removing server socket
     files.
    </P
></LI
><LI
><P
>Enable PAM for Mac OS X (Aaron Hillegass)</P
></LI
><LI
><P
>Make B-tree indexes fully WAL-safe (Tom)</P
><P
>     In prior releases, under certain rare cases, a server crash
     could cause B-tree indexes to become corrupt. This release
     removes those last few rare cases.
    </P
></LI
><LI
><P
>Allow B-tree index compaction and empty page reuse (Tom)</P
></LI
><LI
><P
>     Fix inconsistent index lookups during split of first root page (Tom)
    </P
><P
>     In prior releases, when a single-page index split into two
     pages, there was a brief period when another database session
     could miss seeing an index entry.  This release fixes that rare
     failure case.
    </P
></LI
><LI
><P
>Improve free space map allocation logic (Tom)</P
></LI
><LI
><P
>Preserve free space information between server restarts (Tom)</P
><P
>     In prior releases, the free space map was not saved when the
     postmaster was stopped, so newly started servers had no free
     space information. This release saves the free space map, and
     reloads it when the server is restarted.
    </P
></LI
><LI
><P
>Add start time to <TT
CLASS="LITERAL"
>pg_stat_activity</TT
> (Neil)</P
></LI
><LI
><P
>New code to detect corrupt disk pages; erase with <TT
CLASS="VARNAME"
>zero_damaged_pages</TT
> (Tom)</P
></LI
><LI
><P
>New client/server protocol: faster, no username length limit, allow clean exit from <TT
CLASS="COMMAND"
>COPY</TT
> (Tom)</P
></LI
><LI
><P
>Add transaction status, table ID, column ID to client/server protocol (Tom)</P
></LI
><LI
><P
>Add binary I/O to client/server protocol (Tom)</P
></LI
><LI
><P
>Remove autocommit server setting; move to client applications (Tom)</P
></LI
><LI
><P
>New error message wording, error codes, and three levels of error detail (Tom, Joe, Peter)</P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN125868"
>E.145.3.2. Performance Improvements</A
></H3
><P
></P
><UL
><LI
><P
>Add hashing for <TT
CLASS="LITERAL"
>GROUP BY</TT
> aggregates (Tom)</P
></LI
><LI
><P
>Make nested-loop joins be smarter about multicolumn indexes (Tom)</P
></LI
><LI
><P
>Allow multikey hash joins (Tom)</P
></LI
><LI
><P
>Improve constant folding (Tom)</P
></LI
><LI
><P
>Add ability to inline simple SQL functions (Tom)</P
></LI
><LI
><P
>Reduce memory usage for queries using complex functions (Tom)</P
><P
>     In prior releases, functions returning allocated memory would
     not free it until the query completed. This release allows the
     freeing of function-allocated memory when the function call
     completes, reducing the total memory used by functions.
    </P
></LI
><LI
><P
>Improve GEQO optimizer performance (Tom)</P
><P
>     This release fixes several inefficiencies in the way the GEQO optimizer
     manages potential query paths.
    </P
></LI
><LI
><P
>     Allow <TT
CLASS="LITERAL"
>IN</TT
>/<TT
CLASS="LITERAL"
>NOT IN</TT
> to be handled via hash
     tables (Tom)
    </P
></LI
><LI
><P
>     Improve <TT
CLASS="LITERAL"
>NOT IN (<TT
CLASS="REPLACEABLE"
><I
>subquery</I
></TT
>)</TT
>
     performance (Tom)
    </P
></LI
><LI
><P
>     Allow most <TT
CLASS="LITERAL"
>IN</TT
> subqueries to be processed as
     joins (Tom)
    </P
></LI
><LI
><P
>     Pattern matching operations can use indexes regardless of
     locale (Peter)
    </P
><P
>     There is no way for non-ASCII locales to use the standard
     indexes for <TT
CLASS="LITERAL"
>LIKE</TT
> comparisons. This release
     adds a way to create a special index for
     <TT
CLASS="LITERAL"
>LIKE</TT
>.
    </P
></LI
><LI
><P
>Allow the postmaster to preload libraries using <TT
CLASS="VARNAME"
>preload_libraries</TT
> (Joe)</P
><P
>     For shared libraries that require a long time to load, this
     option is available so the library can be preloaded in the
     postmaster and inherited by all database sessions.
    </P
></LI
><LI
><P
>     Improve optimizer cost computations, particularly for subqueries (Tom)
    </P
></LI
><LI
><P
>     Avoid sort when subquery <TT
CLASS="LITERAL"
>ORDER BY</TT
> matches upper query (Tom)
    </P
></LI
><LI
><P
>     Deduce that <TT
CLASS="LITERAL"
>WHERE a.x = b.y AND b.y = 42</TT
> also
     means <TT
CLASS="LITERAL"
>a.x = 42</TT
> (Tom)
    </P
></LI
><LI
><P
>     Allow hash/merge joins on complex joins (Tom)
    </P
></LI
><LI
><P
>     Allow hash joins for more data types (Tom)
    </P
></LI
><LI
><P
>     Allow join optimization of explicit inner joins, disable with
     <TT
CLASS="VARNAME"
>join_collapse_limit</TT
> (Tom)
    </P
></LI
><LI
><P
>     Add parameter <TT
CLASS="VARNAME"
>from_collapse_limit</TT
> to control
     conversion of subqueries to joins (Tom)
    </P
></LI
><LI
><P
>     Use faster and more powerful regular expression code from Tcl
     (Henry Spencer, Tom)
    </P
></LI
><LI
><P
>     Use bit-mapped relation sets in the optimizer (Tom)
    </P
></LI
><LI
><P
>Improve connection startup time (Tom)</P
><P
>     The new client/server protocol requires fewer network packets to
     start a database session.
    </P
></LI
><LI
><P
>     Improve trigger/constraint performance (Stephan)
    </P
></LI
><LI
><P
>     Improve speed of <TT
CLASS="LITERAL"
>col IN (const, const, const, ...)</TT
> (Tom)
    </P
></LI
><LI
><P
>     Fix hash indexes which were broken in rare cases (Tom)
    </P
></LI
><LI
><P
>Improve hash index concurrency and speed (Tom)</P
><P
>     Prior releases suffered from poor hash index performance,
     particularly for high concurrency situations. This release fixes
     that, and the development group is interested in reports
     comparing B-tree and hash index performance.
    </P
></LI
><LI
><P
>Align shared buffers on 32-byte boundary for copy speed improvement (Manfred Spraul)</P
><P
>     Certain CPU's perform faster data copies when addresses are
     32-byte aligned.
    </P
></LI
><LI
><P
>Data type <TT
CLASS="TYPE"
>numeric</TT
> reimplemented for better performance (Tom)</P
><P
>     <TT
CLASS="TYPE"
>numeric</TT
> used to be stored in base 100. The new code
     uses base 10000, for significantly better performance.
    </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN125952"
>E.145.3.3. Server Configuration Changes</A
></H3
><P
></P
><UL
><LI
><P
>Rename server parameter <TT
CLASS="VARNAME"
>server_min_messages</TT
> to <TT
CLASS="VARNAME"
>log_min_messages</TT
> (Bruce)</P
><P
>     This was done so most parameters that control the server logs
     begin with <TT
CLASS="LITERAL"
>log_</TT
>.
    </P
></LI
><LI
><P
>Rename <TT
CLASS="VARNAME"
>show_*_stats</TT
> to <TT
CLASS="VARNAME"
>log_*_stats</TT
> (Bruce)</P
></LI
><LI
><P
>Rename <TT
CLASS="VARNAME"
>show_source_port</TT
> to <TT
CLASS="VARNAME"
>log_source_port</TT
> (Bruce)</P
></LI
><LI
><P
>Rename <TT
CLASS="VARNAME"
>hostname_lookup</TT
> to <TT
CLASS="VARNAME"
>log_hostname</TT
> (Bruce)</P
></LI
><LI
><P
>Add <TT
CLASS="VARNAME"
>checkpoint_warning</TT
> to warn of excessive checkpointing (Bruce)</P
><P
>     In prior releases, it was difficult to determine if checkpoint
     was happening too frequently. This feature adds a warning to the
     server logs when excessive checkpointing happens.
    </P
></LI
><LI
><P
>New read-only server parameters for localization (Tom)</P
></LI
><LI
><P
>     Change debug server log messages to output as <TT
CLASS="LITERAL"
>DEBUG</TT
>
     rather than <TT
CLASS="LITERAL"
>LOG</TT
> (Bruce)
    </P
></LI
><LI
><P
>Prevent server log variables from being turned off by non-superusers (Bruce)</P
><P
>     This is a security feature so non-superusers cannot disable
     logging that was enabled by the administrator.
    </P
></LI
><LI
><P
>     <TT
CLASS="VARNAME"
>log_min_messages</TT
>/<TT
CLASS="VARNAME"
>client_min_messages</TT
> now
     controls <TT
CLASS="VARNAME"
>debug_*</TT
> output (Bruce)
    </P
><P
>     This centralizes client debug information so all debug output
     can be sent to either the client or server logs.
    </P
></LI
><LI
><P
>Add Mac OS X Rendezvous server support (Chris Campbell)</P
><P
>     This allows Mac OS X hosts to query the network for available
     <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> servers.
    </P
></LI
><LI
><P
>     Add ability to print only slow statements using
     <TT
CLASS="VARNAME"
>log_min_duration_statement</TT
>
     (Christopher)
    </P
><P
>     This is an often requested debugging feature that allows
     administrators to see only slow queries in their server logs.
    </P
></LI
><LI
><P
>Allow <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> to accept netmasks in CIDR format (Andrew Dunstan)</P
><P
>     This allows administrators to merge the host IP address and
     netmask fields into a single CIDR field in <TT
CLASS="FILENAME"
>pg_hba.conf</TT
>.
    </P
></LI
><LI
><P
>New read-only parameter <TT
CLASS="VARNAME"
>is_superuser</TT
> (Tom)</P
></LI
><LI
><P
>New parameter <TT
CLASS="VARNAME"
>log_error_verbosity</TT
> to control error detail (Tom)</P
><P
>     This works with the new error reporting feature to supply
     additional error information like hints, file names and line
     numbers.
    </P
></LI
><LI
><P
><TT
CLASS="LITERAL"
>postgres --describe-config</TT
> now dumps server config variables (Aizaz Ahmed, Peter)</P
><P
>     This option is useful for administration tools that need to know
     the configuration variable names and their minimums, maximums,
     defaults, and descriptions.
    </P
></LI
><LI
><P
>     Add new columns in <TT
CLASS="LITERAL"
>pg_settings</TT
>:
     <TT
CLASS="LITERAL"
>context</TT
>, <TT
CLASS="LITERAL"
>type</TT
>, <TT
CLASS="LITERAL"
>source</TT
>,
     <TT
CLASS="LITERAL"
>min_val</TT
>, <TT
CLASS="LITERAL"
>max_val</TT
> (Joe)
    </P
></LI
><LI
><P
>     Make default <TT
CLASS="VARNAME"
>shared_buffers</TT
> 1000 and
     <TT
CLASS="VARNAME"
>max_connections</TT
> 100, if possible (Tom)
    </P
><P
>     Prior versions defaulted to 64 shared buffers so <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
     would start on even very old systems. This release tests the
     amount of shared memory allowed by the platform and selects more
     reasonable default values if possible.  Of course, users are
     still encouraged to evaluate their resource load and size
     <TT
CLASS="VARNAME"
>shared_buffers</TT
> accordingly.
    </P
></LI
><LI
><P
>     New <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> record type
     <TT
CLASS="LITERAL"
>hostnossl</TT
> to prevent SSL connections (Jon
     Jensen)
    </P
><P
>     In prior releases, there was no way to prevent SSL connections
     if both the client and server supported SSL. This option allows
     that capability.
    </P
></LI
><LI
><P
>     Remove parameter <TT
CLASS="VARNAME"
>geqo_random_seed</TT
>
     (Tom)
    </P
></LI
><LI
><P
>     Add server parameter <TT
CLASS="VARNAME"
>regex_flavor</TT
> to control regular expression processing (Tom)
    </P
></LI
><LI
><P
>     Make <TT
CLASS="COMMAND"
>pg_ctl</TT
> better handle nonstandard ports (Greg)
    </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126045"
>E.145.3.4. Query Changes</A
></H3
><P
></P
><UL
><LI
><P
>New SQL-standard information schema (Peter)</P
></LI
><LI
><P
>Add read-only transactions (Peter)</P
></LI
><LI
><P
>Print key name and value in foreign-key violation messages (Dmitry Tkach)</P
></LI
><LI
><P
>Allow users to see their own queries in <TT
CLASS="LITERAL"
>pg_stat_activity</TT
> (Kevin Brown)</P
><P
>     In prior releases, only the superuser could see query strings
     using <TT
CLASS="LITERAL"
>pg_stat_activity</TT
>. Now ordinary users
     can see their own query strings.
    </P
></LI
><LI
><P
>Fix aggregates in subqueries to match SQL standard (Tom)</P
><P
>     The SQL standard says that an aggregate function appearing
     within a nested subquery belongs to the outer query if its
     argument contains only outer-query variables.  Prior
     <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> releases did not handle
     this fine point correctly.
    </P
></LI
><LI
><P
>Add option to prevent auto-addition of tables referenced in query (Nigel J. Andrews)</P
><P
>     By default, tables mentioned in the query are automatically
     added to the <TT
CLASS="LITERAL"
>FROM</TT
> clause if they are not already
     there.  This is compatible with historic
     <SPAN
CLASS="PRODUCTNAME"
>POSTGRES</SPAN
> behavior but is contrary to
     the SQL standard.  This option allows selecting
     standard-compatible behavior.
    </P
></LI
><LI
><P
>Allow <TT
CLASS="LITERAL"
>UPDATE ... SET col = DEFAULT</TT
> (Rod)</P
><P
>     This allows <TT
CLASS="COMMAND"
>UPDATE</TT
> to set a column to its
     declared default value.
    </P
></LI
><LI
><P
>Allow expressions to be used in <TT
CLASS="LITERAL"
>LIMIT</TT
>/<TT
CLASS="LITERAL"
>OFFSET</TT
> (Tom)</P
><P
>     In prior releases, <TT
CLASS="LITERAL"
>LIMIT</TT
>/<TT
CLASS="LITERAL"
>OFFSET</TT
> could
     only use constants, not expressions.
    </P
></LI
><LI
><P
>Implement <TT
CLASS="LITERAL"
>CREATE TABLE AS EXECUTE</TT
> (Neil, Peter)</P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126083"
>E.145.3.5. Object Manipulation Changes</A
></H3
><P
></P
><UL
><LI
><P
>Make <TT
CLASS="COMMAND"
>CREATE SEQUENCE</TT
> grammar more conforming to SQL:2003 (Neil)</P
></LI
><LI
><P
>Add statement-level triggers (Neil)</P
><P
>     While this allows a trigger to fire at the end of a statement,
     it does not allow the trigger to access all rows modified by the
     statement.  This capability is planned for a future release.
    </P
></LI
><LI
><P
>Add check constraints for domains (Rod)</P
><P
>     This greatly increases the usefulness of domains by allowing
     them to use check constraints.
    </P
></LI
><LI
><P
>Add <TT
CLASS="COMMAND"
>ALTER DOMAIN</TT
> (Rod)</P
><P
>     This allows manipulation of existing domains.
    </P
></LI
><LI
><P
>Fix several zero-column table bugs (Tom)</P
><P
>     <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> supports zero-column tables. This fixes various bugs
     that occur when using such tables.
    </P
></LI
><LI
><P
>Have <TT
CLASS="LITERAL"
>ALTER TABLE ... ADD PRIMARY KEY</TT
> add not-null constraint (Rod)</P
><P
>     In prior releases, <TT
CLASS="LITERAL"
>ALTER TABLE ... ADD
     PRIMARY</TT
> would add a unique index, but not a not-null
     constraint.  That is fixed in this release.
    </P
></LI
><LI
><P
>Add <TT
CLASS="LITERAL"
>ALTER TABLE ... WITHOUT OIDS</TT
> (Rod)</P
><P
>     This allows control over whether new and updated rows will have
     an OID column.  This is most useful for saving storage space.
    </P
></LI
><LI
><P
>     Add <TT
CLASS="LITERAL"
>ALTER SEQUENCE</TT
> to modify minimum, maximum,
     increment, cache, cycle values (Rod)
    </P
></LI
><LI
><P
>Add <TT
CLASS="LITERAL"
>ALTER TABLE ... CLUSTER ON</TT
> (Alvaro Herrera)</P
><P
>     This command is used by <TT
CLASS="COMMAND"
>pg_dump</TT
> to record the
     cluster column for each table previously clustered. This
     information is used by database-wide cluster to cluster all
     previously clustered tables.
    </P
></LI
><LI
><P
>Improve automatic type casting for domains (Rod, Tom)</P
></LI
><LI
><P
>Allow dollar signs in identifiers, except as first character (Tom)</P
></LI
><LI
><P
>Disallow dollar signs in operator names, so <TT
CLASS="LITERAL"
>x=$1</TT
> works (Tom)</P
></LI
><LI
><P
>     Allow copying table schema using <TT
CLASS="LITERAL"
>LIKE
     <TT
CLASS="REPLACEABLE"
><I
>subtable</I
></TT
></TT
>, also SQL:2003
     feature <TT
CLASS="LITERAL"
>INCLUDING DEFAULTS</TT
> (Rod)
    </P
></LI
><LI
><P
>     Add <TT
CLASS="LITERAL"
>WITH GRANT OPTION</TT
> clause to
     <TT
CLASS="COMMAND"
>GRANT</TT
> (Peter)
    </P
><P
>     This enabled <TT
CLASS="COMMAND"
>GRANT</TT
> to give other users the
     ability to grant privileges on a object.
    </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126138"
>E.145.3.6. Utility Command Changes</A
></H3
><P
></P
><UL
><LI
><P
>Add <TT
CLASS="LITERAL"
>ON COMMIT</TT
> clause to <TT
CLASS="COMMAND"
>CREATE TABLE</TT
> for temporary tables (Gavin)</P
><P
>     This adds the ability for a table to be dropped or all rows
     deleted on transaction commit.
    </P
></LI
><LI
><P
>Allow cursors outside transactions using <TT
CLASS="LITERAL"
>WITH HOLD</TT
> (Neil)</P
><P
>     In previous releases, cursors were removed at the end of the
     transaction that created them. Cursors can now be created with
     the <TT
CLASS="LITERAL"
>WITH HOLD</TT
> option, which allows them to
     continue to be accessed after the creating transaction has
     committed.
    </P
></LI
><LI
><P
><TT
CLASS="LITERAL"
>FETCH 0</TT
> and <TT
CLASS="LITERAL"
>MOVE 0 </TT
> now do nothing (Bruce)</P
><P
>     In previous releases, <TT
CLASS="LITERAL"
>FETCH 0</TT
> fetched all
     remaining rows, and <TT
CLASS="LITERAL"
>MOVE 0</TT
> moved to the end
     of the cursor.
    </P
></LI
><LI
><P
>     Cause <TT
CLASS="COMMAND"
>FETCH</TT
> and <TT
CLASS="COMMAND"
>MOVE</TT
> to
     return the number of rows fetched/moved, or zero if at the
     beginning/end of cursor, per SQL standard (Bruce)
    </P
><P
>     In prior releases, the row count returned by
     <TT
CLASS="COMMAND"
>FETCH</TT
> and <TT
CLASS="COMMAND"
>MOVE</TT
> did not
     accurately reflect the number of rows processed.
    </P
></LI
><LI
><P
>Properly handle <TT
CLASS="LITERAL"
>SCROLL</TT
> with cursors, or
    report an error (Neil)</P
><P
>     Allowing random access (both forward and backward scrolling) to
     some kinds of queries cannot be done without some additional
     work. If <TT
CLASS="LITERAL"
>SCROLL</TT
> is specified when the cursor
     is created, this additional work will be performed. Furthermore,
     if the cursor has been created with <TT
CLASS="LITERAL"
>NO SCROLL</TT
>,
     no random access is allowed.
    </P
></LI
><LI
><P
>     Implement SQL-compatible options <TT
CLASS="LITERAL"
>FIRST</TT
>,
     <TT
CLASS="LITERAL"
>LAST</TT
>, <TT
CLASS="LITERAL"
>ABSOLUTE <TT
CLASS="REPLACEABLE"
><I
>n</I
></TT
></TT
>,
     <TT
CLASS="LITERAL"
>RELATIVE <TT
CLASS="REPLACEABLE"
><I
>n</I
></TT
></TT
> for
     <TT
CLASS="COMMAND"
>FETCH</TT
> and <TT
CLASS="COMMAND"
>MOVE</TT
> (Tom)
    </P
></LI
><LI
><P
>Allow <TT
CLASS="COMMAND"
>EXPLAIN</TT
> on <TT
CLASS="COMMAND"
>DECLARE CURSOR</TT
> (Tom)</P
></LI
><LI
><P
>Allow <TT
CLASS="COMMAND"
>CLUSTER</TT
> to use index marked as pre-clustered by default (Alvaro Herrera)</P
></LI
><LI
><P
>Allow <TT
CLASS="COMMAND"
>CLUSTER</TT
> to cluster all tables (Alvaro Herrera)</P
><P
>     This allows all previously clustered tables in a database to be
     reclustered with a single command.
    </P
></LI
><LI
><P
>Prevent <TT
CLASS="COMMAND"
>CLUSTER</TT
> on partial indexes (Tom)</P
></LI
><LI
><P
>Allow DOS and Mac line-endings in <TT
CLASS="COMMAND"
>COPY</TT
> files (Bruce)</P
></LI
><LI
><P
>     Disallow literal carriage return as a data value,
     backslash-carriage-return and <TT
CLASS="LITERAL"
>\r</TT
> are still allowed
     (Bruce)
    </P
></LI
><LI
><P
><TT
CLASS="COMMAND"
>COPY</TT
> changes (binary, <TT
CLASS="LITERAL"
>\.</TT
>) (Tom)</P
></LI
><LI
><P
>Recover from <TT
CLASS="COMMAND"
>COPY</TT
> failure cleanly (Tom)</P
></LI
><LI
><P
>Prevent possible memory leaks in <TT
CLASS="COMMAND"
>COPY</TT
> (Tom)</P
></LI
><LI
><P
>Make <TT
CLASS="COMMAND"
>TRUNCATE</TT
> transaction-safe (Rod)</P
><P
>     <TT
CLASS="COMMAND"
>TRUNCATE</TT
> can now be used inside a
     transaction. If the transaction aborts, the changes made by the
     <TT
CLASS="COMMAND"
>TRUNCATE</TT
> are automatically rolled back.
    </P
></LI
><LI
><P
>     Allow prepare/bind of utility commands like
     <TT
CLASS="COMMAND"
>FETCH</TT
> and <TT
CLASS="COMMAND"
>EXPLAIN</TT
> (Tom)
    </P
></LI
><LI
><P
>Add <TT
CLASS="COMMAND"
>EXPLAIN EXECUTE</TT
> (Neil)</P
></LI
><LI
><P
>Improve <TT
CLASS="COMMAND"
>VACUUM</TT
> performance on indexes by reducing WAL traffic (Tom)</P
></LI
><LI
><P
>Functional indexes have been generalized into indexes on expressions (Tom)</P
><P
>     In prior releases, functional indexes only supported a simple
     function applied to one or more column names.  This release
     allows any type of scalar expression.
    </P
></LI
><LI
><P
>     Have <TT
CLASS="COMMAND"
>SHOW TRANSACTION ISOLATION</TT
> match input
     to <TT
CLASS="COMMAND"
>SET TRANSACTION ISOLATION</TT
>
     (Tom)
    </P
></LI
><LI
><P
>      Have <TT
CLASS="COMMAND"
>COMMENT ON DATABASE</TT
> on nonlocal
      database generate a warning, rather than an error (Rod)
     </P
><P
>     Database comments are stored in database-local tables so
     comments on a database have to be stored in each database.
    </P
></LI
><LI
><P
>     Improve reliability of <TT
CLASS="COMMAND"
>LISTEN</TT
>/<TT
CLASS="COMMAND"
>NOTIFY</TT
> (Tom)
    </P
></LI
><LI
><P
>Allow <TT
CLASS="COMMAND"
>REINDEX</TT
> to reliably reindex nonshared system catalog indexes (Tom)</P
><P
>     This allows system tables to be reindexed without the
     requirement of a standalone session, which was necessary in
     previous releases. The only tables that now require a standalone
     session for reindexing are the global system tables
     <TT
CLASS="LITERAL"
>pg_database</TT
>, <TT
CLASS="LITERAL"
>pg_shadow</TT
>, and
     <TT
CLASS="LITERAL"
>pg_group</TT
>.
    </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126249"
>E.145.3.7. Data Type and Function Changes</A
></H3
><P
></P
><UL
><LI
><P
>     New server parameter <TT
CLASS="VARNAME"
>extra_float_digits</TT
> to
     control precision display of floating-point numbers (Pedro
     Ferreira, Tom)
    </P
><P
>     This controls output precision which was causing regression
     testing problems.
    </P
></LI
><LI
><P
>Allow <TT
CLASS="LITERAL"
>+1300</TT
> as a numeric time-zone specifier, for FJST (Tom)</P
></LI
><LI
><P
>     Remove rarely used functions <CODE
CLASS="FUNCTION"
>oidrand</CODE
>,
     <CODE
CLASS="FUNCTION"
>oidsrand</CODE
>, and <CODE
CLASS="FUNCTION"
>userfntest</CODE
> functions
     (Neil)
    </P
></LI
><LI
><P
>Add <CODE
CLASS="FUNCTION"
>md5()</CODE
> function to main server, already in <TT
CLASS="FILENAME"
>contrib/pgcrypto</TT
> (Joe)</P
><P
>     An MD5 function was frequently requested. For more complex
     encryption capabilities, use
     <TT
CLASS="FILENAME"
>contrib/pgcrypto</TT
>.
    </P
></LI
><LI
><P
>Increase date range of <TT
CLASS="TYPE"
>timestamp</TT
> (John Cochran)</P
></LI
><LI
><P
>     Change <TT
CLASS="LITERAL"
>EXTRACT(EPOCH FROM timestamp)</TT
> so
     <TT
CLASS="TYPE"
>timestamp without time zone</TT
> is assumed to be in
     local time, not GMT (Tom)
    </P
></LI
><LI
><P
>Trap division by zero in case the operating system doesn't prevent it (Tom)</P
></LI
><LI
><P
>Change the <TT
CLASS="TYPE"
>numeric</TT
> data type internally to base 10000 (Tom)</P
></LI
><LI
><P
>New <CODE
CLASS="FUNCTION"
>hostmask()</CODE
> function (Greg Wickham)</P
></LI
><LI
><P
>Fixes for <CODE
CLASS="FUNCTION"
>to_char()</CODE
> and <CODE
CLASS="FUNCTION"
>to_timestamp()</CODE
> (Karel)</P
></LI
><LI
><P
>     Allow functions that can take any argument data type and return
     any data type, using <TT
CLASS="TYPE"
>anyelement</TT
> and
     <TT
CLASS="TYPE"
>anyarray</TT
> (Joe)
    </P
><P
>     This allows the creation of functions that can work with any
     data type.
    </P
></LI
><LI
><P
>     Arrays can now be specified as <TT
CLASS="LITERAL"
>ARRAY[1,2,3]</TT
>,
     <TT
CLASS="LITERAL"
>ARRAY[['a','b'],['c','d']]</TT
>, or
     <TT
CLASS="LITERAL"
>ARRAY[ARRAY[ARRAY[2]]]</TT
> (Joe)
    </P
></LI
><LI
><P
>     Allow proper comparisons for arrays, including <TT
CLASS="LITERAL"
>ORDER
     BY</TT
> and <TT
CLASS="LITERAL"
>DISTINCT</TT
> support
     (Joe)
    </P
></LI
><LI
><P
>Allow indexes on array columns (Joe)</P
></LI
><LI
><P
>Allow array concatenation with <TT
CLASS="LITERAL"
>||</TT
> (Joe)</P
></LI
><LI
><P
>     Allow <TT
CLASS="LITERAL"
>WHERE</TT
> qualification
     <TT
CLASS="LITERAL"
><TT
CLASS="REPLACEABLE"
><I
>expr</I
></TT
> <TT
CLASS="REPLACEABLE"
><I
>op</I
></TT
> ANY/SOME/ALL
     (<TT
CLASS="REPLACEABLE"
><I
>array_expr</I
></TT
>)</TT
> (Joe)
    </P
><P
>     This allows arrays to behave like a list of values, for purposes
     like <TT
CLASS="LITERAL"
>SELECT * FROM tab WHERE col IN
     (array_val)</TT
>.
    </P
></LI
><LI
><P
>     New array functions <CODE
CLASS="FUNCTION"
>array_append</CODE
>,
     <CODE
CLASS="FUNCTION"
>array_cat</CODE
>, <CODE
CLASS="FUNCTION"
>array_lower</CODE
>,
     <CODE
CLASS="FUNCTION"
>array_prepend</CODE
>, <CODE
CLASS="FUNCTION"
>array_to_string</CODE
>,
     <CODE
CLASS="FUNCTION"
>array_upper</CODE
>, <CODE
CLASS="FUNCTION"
>string_to_array</CODE
> (Joe)
    </P
></LI
><LI
><P
>Allow user defined aggregates to use polymorphic functions (Joe)</P
></LI
><LI
><P
>Allow assignments to empty arrays (Joe)</P
></LI
><LI
><P
>     Allow 60 in seconds fields of <TT
CLASS="TYPE"
>time</TT
>,
     <TT
CLASS="TYPE"
>timestamp</TT
>, and <TT
CLASS="TYPE"
>interval</TT
> input values
     (Tom)
    </P
><P
>     Sixty-second values are needed for leap seconds.
    </P
></LI
><LI
><P
>Allow <TT
CLASS="TYPE"
>cidr</TT
> data type to be cast to <TT
CLASS="TYPE"
>text</TT
> (Tom)</P
></LI
><LI
><P
>Disallow invalid time zone names in SET TIMEZONE</P
></LI
><LI
><P
>     Trim trailing spaces when <TT
CLASS="TYPE"
>char</TT
> is cast to
     <TT
CLASS="TYPE"
>varchar</TT
> or <TT
CLASS="TYPE"
>text</TT
> (Tom)
    </P
></LI
><LI
><P
>     Make <TT
CLASS="TYPE"
>float(<TT
CLASS="REPLACEABLE"
><I
>p</I
></TT
>)</TT
> measure the precision
     <TT
CLASS="REPLACEABLE"
><I
>p</I
></TT
> in binary digits, not decimal digits
     (Tom)
    </P
></LI
><LI
><P
>Add IPv6 support to the <TT
CLASS="TYPE"
>inet</TT
> and <TT
CLASS="TYPE"
>cidr</TT
> data types (Michael Graff)</P
></LI
><LI
><P
>Add <CODE
CLASS="FUNCTION"
>family()</CODE
> function to report whether address is IPv4 or IPv6 (Michael Graff)</P
></LI
><LI
><P
>     Have <TT
CLASS="LITERAL"
>SHOW datestyle</TT
> generate output similar
     to that used by <TT
CLASS="LITERAL"
>SET datestyle</TT
> (Tom)
    </P
></LI
><LI
><P
>     Make <TT
CLASS="LITERAL"
>EXTRACT(TIMEZONE)</TT
> and <TT
CLASS="LITERAL"
>SET/SHOW
     TIME ZONE</TT
> follow the SQL convention for the sign of
     time zone offsets, i.e., positive is east from UTC (Tom)
    </P
></LI
><LI
><P
>Fix <TT
CLASS="LITERAL"
>date_trunc('quarter', ...)</TT
> (B&ouml;jthe Zolt&aacute;n)</P
><P
>     Prior releases returned an incorrect value for this function call.
    </P
></LI
><LI
><P
>Make <CODE
CLASS="FUNCTION"
>initcap()</CODE
> more compatible with Oracle (Mike Nolan)</P
><P
>     <CODE
CLASS="FUNCTION"
>initcap()</CODE
> now uppercases a letter appearing
     after any non-alphanumeric character, rather than only after
     whitespace.
    </P
></LI
><LI
><P
>Allow only <TT
CLASS="VARNAME"
>datestyle</TT
> field order for date values not in ISO-8601 format (Greg)</P
></LI
><LI
><P
>     Add new <TT
CLASS="VARNAME"
>datestyle</TT
> values <TT
CLASS="LITERAL"
>MDY</TT
>,
     <TT
CLASS="LITERAL"
>DMY</TT
>, and <TT
CLASS="LITERAL"
>YMD</TT
> to set input field order;
     honor <TT
CLASS="LITERAL"
>US</TT
> and <TT
CLASS="LITERAL"
>European</TT
> for backward
     compatibility (Tom)
    </P
></LI
><LI
><P
>     String literals like <TT
CLASS="LITERAL"
>'now'</TT
> or
     <TT
CLASS="LITERAL"
>'today'</TT
> will no longer work as a column
     default. Use functions such as <CODE
CLASS="FUNCTION"
>now()</CODE
>,
     <CODE
CLASS="FUNCTION"
>current_timestamp</CODE
> instead.  (change
     required for prepared statements) (Tom)
    </P
></LI
><LI
><P
>Treat NaN as larger than any other value in <CODE
CLASS="FUNCTION"
>min()</CODE
>/<CODE
CLASS="FUNCTION"
>max()</CODE
> (Tom)</P
><P
>     NaN was already sorted after ordinary numeric values for most
     purposes, but <CODE
CLASS="FUNCTION"
>min()</CODE
> and <CODE
CLASS="FUNCTION"
>max()</CODE
> didn't
     get this right.
    </P
></LI
><LI
><P
>Prevent interval from suppressing <TT
CLASS="LITERAL"
>:00</TT
>
    seconds display</P
></LI
><LI
><P
>     New functions <CODE
CLASS="FUNCTION"
>pg_get_triggerdef(prettyprint)</CODE
>
     and <CODE
CLASS="FUNCTION"
>pg_conversion_is_visible()</CODE
> (Christopher)
    </P
></LI
><LI
><P
>Allow time to be specified as <TT
CLASS="LITERAL"
>040506</TT
> or <TT
CLASS="LITERAL"
>0405</TT
> (Tom)</P
></LI
><LI
><P
>     Input date order must now be <TT
CLASS="LITERAL"
>YYYY-MM-DD</TT
> (with 4-digit year) or
     match <TT
CLASS="VARNAME"
>datestyle</TT
>
    </P
></LI
><LI
><P
>     Make <CODE
CLASS="FUNCTION"
>pg_get_constraintdef</CODE
> support
     unique, primary-key, and check constraints (Christopher)
    </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126418"
>E.145.3.8. Server-Side Language Changes</A
></H3
><P
></P
><UL
><LI
><P
>     Prevent PL/pgSQL crash when <TT
CLASS="LITERAL"
>RETURN NEXT</TT
> is
     used on a zero-row record variable (Tom)
    </P
></LI
><LI
><P
>     Make PL/Python's <CODE
CLASS="FUNCTION"
>spi_execute</CODE
> interface
     handle null values properly (Andrew Bosma)
    </P
></LI
><LI
><P
>Allow PL/pgSQL to declare variables of composite types without <TT
CLASS="LITERAL"
>%ROWTYPE</TT
> (Tom)</P
></LI
><LI
><P
>Fix PL/Python's <CODE
CLASS="FUNCTION"
>_quote()</CODE
> function to handle big integers</P
></LI
><LI
><P
>Make PL/Python an untrusted language, now called <TT
CLASS="LITERAL"
>plpythonu</TT
> (Kevin Jacobs, Tom)</P
><P
>     The Python language no longer supports a restricted execution
     environment, so the trusted version of PL/Python was removed. If
     this situation changes, a version of PL/Python that can be used
     by non-superusers will be readded.
    </P
></LI
><LI
><P
>Allow polymorphic PL/pgSQL functions (Joe, Tom)</P
></LI
><LI
><P
>Allow polymorphic SQL functions (Joe)</P
></LI
><LI
><P
>     Improved compiled function caching mechanism in PL/pgSQL with
     full support for polymorphism (Joe)
    </P
></LI
><LI
><P
>     Add new parameter <TT
CLASS="LITERAL"
>$0</TT
> in PL/pgSQL representing the
     function's actual return type (Joe)
    </P
></LI
><LI
><P
>     Allow PL/Tcl and PL/Python to use the same trigger on multiple tables (Tom)
    </P
></LI
><LI
><P
>     Fixed PL/Tcl's <CODE
CLASS="FUNCTION"
>spi_prepare</CODE
> to accept fully
     qualified type names in the parameter type list
     (Jan)
    </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126451"
>E.145.3.9. psql Changes</A
></H3
><P
></P
><UL
><LI
><P
>Add <TT
CLASS="LITERAL"
>\pset pager always</TT
> to always use pager (Greg)</P
><P
>     This forces the pager to be used even if the number of rows is
     less than the screen height.  This is valuable for rows that
     wrap across several screen rows.
    </P
></LI
><LI
><P
>Improve tab completion (Rod, Ross Reedstrom, Ian Barwick)</P
></LI
><LI
><P
>Reorder <TT
CLASS="LITERAL"
>\?</TT
> help into groupings (Harald Armin Massa, Bruce)</P
></LI
><LI
><P
>Add backslash commands for listing schemas, casts, and conversions (Christopher)</P
></LI
><LI
><P
>     <TT
CLASS="COMMAND"
>\encoding</TT
> now changes based on the server parameter
     <TT
CLASS="VARNAME"
>client_encoding</TT
> (Tom)
    </P
><P
>     In previous versions, <TT
CLASS="COMMAND"
>\encoding</TT
> was not aware
     of encoding changes made using <TT
CLASS="LITERAL"
>SET
     client_encoding</TT
>.
    </P
></LI
><LI
><P
>Save editor buffer into readline history (Ross)</P
><P
>     When <TT
CLASS="COMMAND"
>\e</TT
> is used to edit a query, the result is saved
     in the readline history for retrieval using the up arrow.
    </P
></LI
><LI
><P
>Improve <TT
CLASS="COMMAND"
>\d</TT
> display (Christopher)</P
></LI
><LI
><P
>Enhance HTML mode to be more standards-conforming (Greg)</P
></LI
><LI
><P
>New <TT
CLASS="COMMAND"
>\set AUTOCOMMIT off</TT
> capability (Tom)</P
><P
>     This takes the place of the removed server parameter <TT
CLASS="VARNAME"
>autocommit</TT
>.
    </P
></LI
><LI
><P
>New <TT
CLASS="COMMAND"
>\set VERBOSITY</TT
> to control error detail (Tom)</P
><P
>     This controls the new error reporting details.
    </P
></LI
><LI
><P
>New prompt escape sequence <TT
CLASS="LITERAL"
>%x</TT
> to show transaction status (Tom)</P
></LI
><LI
><P
>Long options for <SPAN
CLASS="APPLICATION"
>psql</SPAN
> are now available on all platforms</P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126496"
>E.145.3.10. pg_dump Changes</A
></H3
><P
></P
><UL
><LI
><P
>Multiple pg_dump fixes, including tar format and large objects</P
></LI
><LI
><P
>Allow pg_dump to dump specific schemas (Neil)</P
></LI
><LI
><P
>Make pg_dump preserve column storage characteristics (Christopher)</P
><P
>     This preserves <TT
CLASS="LITERAL"
>ALTER TABLE ... SET STORAGE</TT
> information.
    </P
></LI
><LI
><P
>Make pg_dump preserve <TT
CLASS="COMMAND"
>CLUSTER</TT
> characteristics (Christopher)</P
></LI
><LI
><P
>     Have pg_dumpall use <TT
CLASS="COMMAND"
>GRANT</TT
>/<TT
CLASS="COMMAND"
>REVOKE</TT
> to dump database-level privileges (Tom)
    </P
></LI
><LI
><P
>     Allow pg_dumpall to support the options <TT
CLASS="OPTION"
>-a</TT
>,
     <TT
CLASS="OPTION"
>-s</TT
>, <TT
CLASS="OPTION"
>-x</TT
> of pg_dump (Tom)
    </P
></LI
><LI
><P
>Prevent pg_dump from lowercasing identifiers specified on the command line (Tom)</P
></LI
><LI
><P
>     pg_dump options <TT
CLASS="OPTION"
>--use-set-session-authorization</TT
>
     and <TT
CLASS="OPTION"
>--no-reconnect</TT
> now do nothing, all dumps
     use <TT
CLASS="COMMAND"
>SET SESSION AUTHORIZATION</TT
>
    </P
><P
>     pg_dump no longer reconnects to switch users, but instead always
     uses <TT
CLASS="COMMAND"
>SET SESSION AUTHORIZATION</TT
>. This will
     reduce password prompting during restores.
    </P
></LI
><LI
><P
>Long options for <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> are now available on all platforms</P
><P
>     <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> now includes its own
     long-option processing routines.
    </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126533"
>E.145.3.11. libpq Changes</A
></H3
><P
></P
><UL
><LI
><P
>     Add function <CODE
CLASS="FUNCTION"
>PQfreemem</CODE
> for freeing memory on
     Windows, suggested for <TT
CLASS="COMMAND"
>NOTIFY</TT
> (Bruce)
    </P
><P
>     Windows requires that memory allocated in a library be freed by
     a function in the same library, hence
     <CODE
CLASS="FUNCTION"
>free()</CODE
> doesn't work for freeing memory
     allocated by libpq. <CODE
CLASS="FUNCTION"
>PQfreemem</CODE
> is the proper
     way to free libpq memory, especially on Windows, and is
     recommended for other platforms as well.
    </P
></LI
><LI
><P
>Document service capability, and add sample file (Bruce)</P
><P
>     This allows clients to look up connection information in a
     central file on the client machine.
    </P
></LI
><LI
><P
>     Make <CODE
CLASS="FUNCTION"
>PQsetdbLogin</CODE
> have the same defaults as
     <CODE
CLASS="FUNCTION"
>PQconnectdb</CODE
> (Tom)
    </P
></LI
><LI
><P
>Allow libpq to cleanly fail when result sets are too large (Tom)</P
></LI
><LI
><P
>     Improve performance of function <CODE
CLASS="FUNCTION"
>PQunescapeBytea</CODE
> (Ben Lamb)
    </P
></LI
><LI
><P
>     Allow thread-safe libpq with <TT
CLASS="FILENAME"
>configure</TT
>
     option <TT
CLASS="OPTION"
>--enable-thread-safety</TT
> (Lee Kindness,
     Philip Yarra)
    </P
></LI
><LI
><P
>     Allow function <CODE
CLASS="FUNCTION"
>pqInternalNotice</CODE
> to accept a
     format string and arguments instead of just a preformatted
     message (Tom, Sean Chittenden)
    </P
></LI
><LI
><P
>     Control SSL negotiation with <TT
CLASS="LITERAL"
>sslmode</TT
> values
     <TT
CLASS="LITERAL"
>disable</TT
>, <TT
CLASS="LITERAL"
>allow</TT
>,
     <TT
CLASS="LITERAL"
>prefer</TT
>, and <TT
CLASS="LITERAL"
>require</TT
> (Jon
     Jensen)
    </P
></LI
><LI
><P
>Allow new error codes and levels of text (Tom)</P
></LI
><LI
><P
>Allow access to the underlying table and column of a query result (Tom)</P
><P
>     This is helpful for query-builder applications that want to know
     the underlying table and column names associated with a specific
     result set.
    </P
></LI
><LI
><P
>Allow access to the current transaction status (Tom)</P
></LI
><LI
><P
>Add ability to pass binary data directly to the server (Tom)</P
></LI
><LI
><P
>     Add function <CODE
CLASS="FUNCTION"
>PQexecPrepared</CODE
> and
     <CODE
CLASS="FUNCTION"
>PQsendQueryPrepared</CODE
> functions which perform
     bind/execute of previously prepared statements (Tom)
     </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126582"
>E.145.3.12. JDBC Changes</A
></H3
><P
></P
><UL
><LI
><P
>Allow <CODE
CLASS="FUNCTION"
>setNull</CODE
> on updateable result sets</P
></LI
><LI
><P
>Allow <CODE
CLASS="FUNCTION"
>executeBatch</CODE
> on a prepared statement (Barry)</P
></LI
><LI
><P
>Support SSL connections (Barry)</P
></LI
><LI
><P
>Handle schema names in result sets (Paul Sorenson)</P
></LI
><LI
><P
>Add refcursor support (Nic Ferrier)</P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126597"
>E.145.3.13. Miscellaneous Interface Changes</A
></H3
><P
></P
><UL
><LI
><P
>Prevent possible memory leak or core dump during libpgtcl shutdown (Tom)</P
></LI
><LI
><P
>Add Informix compatibility to ECPG (Michael)</P
><P
>     This allows ECPG to process embedded C programs that were
     written using certain Informix extensions.
    </P
></LI
><LI
><P
>Add type <TT
CLASS="TYPE"
>decimal</TT
> to ECPG that is fixed length, for Informix (Michael)</P
></LI
><LI
><P
>     Allow thread-safe embedded SQL programs with
     <TT
CLASS="FILENAME"
>configure</TT
> option
     <TT
CLASS="OPTION"
>--enable-thread-safety</TT
> (Lee Kindness, Bruce)
    </P
><P
>     This allows multiple threads to access the database at the same
     time.
    </P
></LI
><LI
><P
>Moved Python client PyGreSQL to <A
HREF="http://www.pygresql.org"
TARGET="_top"
>http://www.pygresql.org</A
> (Marc)</P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126616"
>E.145.3.14. Source Code Changes</A
></H3
><P
></P
><UL
><LI
><P
>Prevent need for separate platform geometry regression result files (Tom)</P
></LI
><LI
><P
>Improved PPC locking primitive (Reinhard Max)</P
></LI
><LI
><P
>New function <CODE
CLASS="FUNCTION"
>palloc0</CODE
> to allocate and clear memory (Bruce)</P
></LI
><LI
><P
>Fix locking code for s390x CPU (64-bit) (Tom)</P
></LI
><LI
><P
>Allow OpenBSD to use local ident credentials (William Ahern)</P
></LI
><LI
><P
>Make query plan trees read-only to executor (Tom)</P
></LI
><LI
><P
>Add Darwin startup scripts (David Wheeler)</P
></LI
><LI
><P
>Allow libpq to compile with Borland C++ compiler (Lester Godwin, Karl Waclawek)</P
></LI
><LI
><P
>Use our own version of <CODE
CLASS="FUNCTION"
>getopt_long()</CODE
> if needed (Peter)</P
></LI
><LI
><P
>Convert administration scripts to C (Peter)</P
></LI
><LI
><P
> Bison &gt;= 1.85 is now required to build the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> grammar, if building from CVS</P
></LI
><LI
><P
>Merge documentation into one book (Peter)</P
></LI
><LI
><P
>Add Windows compatibility functions (Bruce)</P
></LI
><LI
><P
>Allow client interfaces to compile under MinGW (Bruce)</P
></LI
><LI
><P
>New <CODE
CLASS="FUNCTION"
>ereport()</CODE
> function for error reporting (Tom)</P
></LI
><LI
><P
>Support Intel compiler on Linux (Peter)</P
></LI
><LI
><P
>Improve Linux startup scripts (Slawomir Sudnik, Darko Prenosil)</P
></LI
><LI
><P
>Add support for AMD Opteron and Itanium (Jeffrey W. Baker, Bruce)</P
></LI
><LI
><P
>Remove <TT
CLASS="OPTION"
>--enable-recode</TT
> option from <TT
CLASS="COMMAND"
>configure</TT
></P
><P
>     This was no longer needed now that we have <TT
CLASS="COMMAND"
>CREATE CONVERSION</TT
>.
    </P
></LI
><LI
><P
>Generate a compile error if spinlock code is not found (Bruce)</P
><P
>     Platforms without spinlock code will now fail to compile, rather
     than silently using semaphores. This failure can be disabled
     with a new <TT
CLASS="COMMAND"
>configure</TT
> option.
    </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN126669"
>E.145.3.15. Contrib Changes</A
></H3
><P
></P
><UL
><LI
><P
>Change dbmirror license to BSD</P
></LI
><LI
><P
>Improve earthdistance (Bruno Wolff III)</P
></LI
><LI
><P
>Portability improvements to pgcrypto (Marko Kreen)</P
></LI
><LI
><P
>Prevent crash in xml (John Gray, Michael Richards)</P
></LI
><LI
><P
>Update oracle</P
></LI
><LI
><P
>Update mysql</P
></LI
><LI
><P
>Update cube (Bruno Wolff III)</P
></LI
><LI
><P
>Update earthdistance to use cube (Bruno Wolff III)</P
></LI
><LI
><P
>Update btree_gist (Oleg)</P
></LI
><LI
><P
>New tsearch2 full-text search module (Oleg, Teodor)</P
></LI
><LI
><P
>Add hash-based crosstab function to tablefuncs (Joe)</P
></LI
><LI
><P
>Add serial column to order <CODE
CLASS="FUNCTION"
>connectby()</CODE
> siblings in tablefuncs (Nabil Sayegh,Joe)</P
></LI
><LI
><P
>Add named persistent connections to dblink (Shridhar Daithanka)</P
></LI
><LI
><P
>New pg_autovacuum allows automatic <TT
CLASS="COMMAND"
>VACUUM</TT
> (Matthew T. O'Connor)</P
></LI
><LI
><P
>Make pgbench honor environment variables <TT
CLASS="ENVAR"
>PGHOST</TT
>, <TT
CLASS="ENVAR"
>PGPORT</TT
>, <TT
CLASS="ENVAR"
>PGUSER</TT
> (Tatsuo)</P
></LI
><LI
><P
>Improve intarray (Teodor Sigaev)</P
></LI
><LI
><P
>Improve pgstattuple (Rod)</P
></LI
><LI
><P
>Fix bug in <CODE
CLASS="FUNCTION"
>metaphone()</CODE
> in fuzzystrmatch</P
></LI
><LI
><P
>Improve adddepend (Rod)</P
></LI
><LI
><P
>Update spi/timetravel (B&ouml;jthe Zolt&aacute;n)</P
></LI
><LI
><P
>Fix dbase <TT
CLASS="OPTION"
>-s</TT
> option and improve non-ASCII handling (Thomas Behr, M&aacute;rcio Smiderle)</P
></LI
><LI
><P
>Remove array module because features now included by default (Joe)</P
></LI
></UL
></DIV
></DIV
></DIV
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